Asbo-lutely mad
One way to imprison a suspected terrorist for 90 days or even longer, without any bother from Parliament, would be to give him an Anti-Social Behaviour Order. The Asbo could be drawn up to include a number of hard-to-follow rules such as never to associate with more than one other person in public or use the internet. Once a breach was proved in court, where it would be regarded as a serious criminal offence, the offender could be given a jail sentence of up to five years. Gotcha! Such is the concealed yet far-reaching power of the Asbo that this is a not entirely frivolous hypothesis.